Producing lithium

ABSTRACT

A electrolytic process for continuous production of lithium metal from lithium carbonate or other lithium salts by use of an aqueous acid electrolyte and a lithium producing cell structure which includes: a cell body with a cathode within the cell body; an electrolyte aqueous solution within the cell body, the solution containing lithium ion and an anion; and a composite layer intercalated between the cathode and the electrolyte aqueous solution, the composite layer comprising a lithium ion conductive glass ceramic (LI-GC) and a lithium ion conductive barrier film (LI-BF) that isolates cathode-forming lithium from the electrolyte aqueous solution.

This application claims the benefit of provisional application Ser. No.61/844,482, filed Jul. 10, 2013, the disclosure of which is incorporatedinto this specification by reference in its entirety.

BACKGROUND OF THE INVENTION

The invention is a continuous process for obtaining lithium metal and acell for carrying out the process.

Lithium is a soft, silver-white metal belonging to the alkali metalgroup of chemical elements. It is the lightest metal and the least densesolid element. Lithium is highly reactive and flammable. Because of itshigh reactivity, it does not occur freely in nature, and instead, onlyappears in compositions, usually ionic in nature. Like the other alkalimetals, lithium has a single valence electron that is easily given up toform a cation. Because of this, it is a good conductor of heat andelectricity as well as a highly reactive element. Because of itsreactivity, lithium is usually stored under cover of a hydrocarbon,often mineral oil. In moist air, lithium rapidly tarnishes to form ablack coating of lithium hydroxide (LiOH and LiOH.H₂O).

Uses of lithium compounds include lithium oxide as a flux for processingsilica to glazes of low coefficients of thermal expansion, lithiumcarbonate (Li₂CO₃), as a component in ovenware and with lithiumhydroxide, which is a strong base that can be heated with a fat toproduce a lithium stearate soap. Lithium soap can be used to thickenoils and in the manufacture of lubricating greases. Metallic lithium canbe used as a flux for welding or soldering to promote fusing of metalsto eliminate oxide formation by absorbing impurities. Its fusing qualityis important as a flux for producing ceramics, enamels and glass.Metallic lithium is used to manufacture primary lithium batteries.

Lithium carbonate is a common form of lithium produced from spodumene orlithium containing brine. Lithium metal can be can be extracted fromlithium carbonate in phases:

Conversion of lithium carbonate into lithium chloride.Electrolysis of lithium chloride.

To convert lithium carbonate to lithium chloride the lithium carbonateis heated and mixed with hydrochloric acid (typically 31% HCL) in anagitated reactor:

Li2CO3(s)+2HCl(aq)→2LiCl(aq)+H2O(aq)+CO₂(g)  (Eq-2)

The formed carbon dioxide is vented from the reactant solution. A smallamount of barium chloride can be added to precipitate any sulfate. Afterfiltering, the solution is evaporated to a saleable 40% LiCl liquidproduct. Potassium chloride can be added to provide a dry lithiumchloride-potassium chloride (45% LiCl; 55% KCl) of decreased meltingpoint (614° C. to approximate 420° C.). Then the lithiumchloride-potassium chloride (45% LiCl; 55% KCl) in a molten pure and drystate can be utilized to produce lithium metal in a steel reaction cell.

One steel cell has exterior ceramic insulation and a steel rod on thebottom as a cathode. The anode is constructed of graphite, which slowlysloughs-off during processing. The cell can be heated by gas firingbetween ceramic insulation and a cell's interior steel wall. Lithiummetal accumulates at the surface of the cell wall and is then pouredinto ingots. Chloride gas generated by reaction is routed away.Typically, the electrolysis process is u operated with a cell voltage of6.7˜7.5V, the typical cell current can be in the range of 30˜60 kA. Theprocessing consumes 30˜35 kWh of electricity energy and 6.2˜6.4 kg LiClto produce one kilogram lithium metal with 20˜40% energy efficiency.

Li⁺ +e ⁻→Li metal  Cathode

Cl⁻→½Cl₂ +e ⁻  Anode

2LiCl→2Li+Cl₂  Total

A low temperature technology involves electrolysis of brine to formchlorine at an anode and sodium hydroxide or potassium hydroxide via aseries of cathode reactions. The formation of either of these hydroxidescan involve the reduction of an alkali cation, e.g. Li⁺ to metal at aliquid mercury cathode, followed by reaction of the formed mercuryamalgam with water. The process operates near room temperature with alower voltage than required for the molten salt system.

Amendola et al. U.S. Pat. No. 8,715,482 provides a system and processthat obviates a mercury electrode. The liquid metal alloy electrodesystem of U.S. Pat. No. 8,715,482 includes: an electrolytic cellcomprising a liquid metal cathode and an aqueous solution wherein theaqueous solution containing lithium ion and at least an anion selectedfrom sulfate, trifluoromethane sulfonate, fluorosulfonate,trifluoroborate, trifluoroacetate, trifluorosilicate and kineticallyhindered acid anions and wherein the lithium ion is produced fromlithium carbonate. A heating system maintains temperature of the celland liquid metal circulating systems higher than the melting point ofthe liquid metal cathode but lower than the boiling point of the aqueoussolution. The reduced lithium from the electrolytic cell is extractedfrom the liquid metal cathode using a suitable extraction solution and adistillation system for isolating the lithium metal. This system issolid at room temperature and is less toxic than previous systems.

Putter et al. U.S. Pat. No. 6,770,187 discloses another process thatovercomes some of the high energy consumption and high temperaturerequirement of prior art processes. The Putter et al process enablesrecycling of alkali metals from aqueous alkali metal waste, inparticular lithium from aqueous lithium waste. Putter et al provides anelectrolysis cell comprising an anode compartment which comprises anaqueous solution of at least one alkali metal salt, a cathodecompartment and an ion conducting solid composite that separates theanode compartment and the cathode compartment from one another, whereinthat part of the surface of the solid electrolyte composite that is incontact with the anode compartment and/or that part of the surface ofthe solid electrolyte that is in contact with the cathode compartmenthas/have at least one further ion-conducting layer. The electrolyte usedin U.S. Pat. No. 6,770,187 is water or water with organic solvent.

Previous lithium producing system have involved substantial capital andoperating costs. There is a need for a direct and improved electrolysisprocess that requires reduced capital and operating costs in a systemthat effectively provides direct production of lithium metal.Additionally, Potter et al. points out that “[a]lkali metal ionconductors of this type are frequently not resistant to water and/or toalkali metals, and the experiment therefore leads to damage of thealkali metal ion conductors after only a short period. This damage cancomprise either mechanical failure of the ion conductor or loss of itsconductivity. A further aim of the current invention therefore is tokeep the ion conductors stable over a prolonged working life.

There is a need for a process that does not have the disadvantagesdescribed above (high energy consumption, high temperature, etc.). Afurther object is to provide an electrolysis cell suitable for carryingout this process.

BRIEF DESCRIPTION OF THE INVENTION

The invention provides an electrolysis cell and process characterized bya selective permeable barrier composite that provides for directrecovery of lithium metal. The cell and process are reasonably energyconsuming and the lithium ion conducting composite layer is stable evenin a highly corrosive anode compartment acid environment. In anembodiment, the invention is a lithium producing cell structure,comprising: a cell body with an anode and cathode within the cell body;an electrolyte aqueous solution within the cell body, the solutioncontaining lithium ion; and a composite layer intercalated between thecathode and the electrolyte aqueous solution, the composite layercomprising a substantially impervious, lithium ion conductive compositelayer (Li-GC) such as a glass ceramic and an active lithium ionconducting separation layer (Li-BF) that isolates cathode-forminglithium from the Li-GC.

In an embodiment, the invention is a process for producing lithium,comprising: providing a lithium ion source (lithium carbonate) and atleast an acid in an aqueous solvent wherein lithium anion is dissolvedin the solvent to form a lithium feed solution; providing an anode incontact with the solution; providing a cathode suitable for electrolysisof lithium; providing an ionizing electric current to the electrolysiscell thereby producing lithium metal at the cathode; and providing acomposite layer transecting an axis of the cell body, the compositelayer, comprising a lithium ion glass ceramic and lithium ion conductivebarrier film that isolates cathode-forming lithium from theanion-containing solution as lithium metal is formed.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 of the drawings is a schematic elevation view of a lithiumproducing cell structure;

FIG. 2 is a schematic detail of the cell structure of FIG. 1; and

FIG. 3 is a schematic exploded detail of a cell of this application.

DETAILED DESCRIPTION OF THE INVENTION

Because of lithium's high electrochemical potential, it is an importantcomponent of electrolyte and electrodes in batteries. A typicallithium-ion battery can generate approximately 3 volts, compared with2.1 volts for lead-acid or 1.5 volts for zinc-carbon cells. Because ofits low atomic mass, it also has a high charge- and power-to-weightratio. Lithium-ion batteries are high energy-density rechargeablebatteries. Other rechargeable battery types include the lithium-ionpolymer battery, lithium iron phosphate battery, and the nanowirebattery.

This invention is for the production of lithium metal from lithiumcarbonate feed stock (or other lithium salt such as lithium chloridewhich dissociates in an acid electrolyte and releases the non-lithiumportion of the feed stock as gas). My process can continuously processlithium carbonate into lithium metal. This is done by using a sulfuricacid electrolyte to disassociate lithium carbonate, placing the lithiumions into solution for processing and venting off the carbonate portionwithout it entering into solution.

The use of sulfuric acid for lithium carbonate processing is important:Lithium carbonate is essentially insoluble in water and organicsolvents. Lithium cannot be efficiently extracted from lithium carbonatesalt using an aqueous electrolyte with or without organic solvent. Useof a sulfuric acid solution provides much higher solubility of lithiumcarbonate into solution allowing efficient production of lithium metalfrom lithium carbonate. By disassociating the lithium carbonate and onlyplacing the lithium ions into solution, the electrolyte solution remainsstable and does not build up a concentration of the non-lithium ionportion of the feed stock. Lithium carbonate can be continuously fedinto a tank outside of the electrolysis cell, venting off the CO₂ gasreleased by the sulfuric acid electrolyte. The acid electrolyte does notneed to be disposed of or replenished, lithium carbonate can becontinuously added to a feed tank, venting off CO2 and harvestinglithium metal from a cathode. This can be continuously operated orconducted as a batch process.

The invention provides a cathode separated from lithium ion richsolution by a selectively permeable barrier composite (LIC-GC-BF). Thecomposite comprises a lithium Ion conductive glass ceramic layer (LI-GC)and a lithium ion conductive barrier film (LI-BF). The LIC-GC-BFcomposite allows for direct production of lithium metal from solutionand direct deposition of lithium metal onto a clean cathode, withoutneed for an additional extraction process. The inventive system caninclude: an electrolyte feed system that provides a lithium ion richelectrolyte to the electrolysis cell; an electrolytic cell to movelithium metal from a water-based lithium ion solution through theLIC-GC-BF composite; and a method to package lithium metal. Theinvention can be part of a continuous lithium metal production processor as a batch process.

Features of the invention will become apparent from the drawings andfollowing detailed discussion, which by way of example withoutlimitation describe preferred embodiments of the invention.

The FIGS. 1 and 2 illustrate a production process of the inventionwherein lithium-rich electrolyte flows through an extraction cell. Whenpotential is applied to the system, lithium metal builds up on a movingcathode below an intercalated composite layer. FIG. 1 of the drawings isa schematic elevation view of lithium producing cell structure and FIG.2 is a schematic detail of the cell structure of FIG. 1. In FIG. 1, andFIG. 2, the electrolytic cell 10 according to an embodiment of theinvention, includes an upper section 12 and lower section 14. The cell10 is characterized by a movable cathode 16 that transects across-section of the cell. The cathode 16 transposes an axis of cell 10,advancing as an electrolysis reaction takes place in electrolyte 18above the cathode 16, through the LIC-GC-BF composite layer. Anode 20 isprovided to the cell upper section 12. The cell section 12 above thecathode 10 is loaded with electrolyte 18 via inlet 22, electrolysisproceeds and spent electrolyte is discharged via outlet 24. The cathode16 is in contact with the electrolyte 18 through a composite layer 28intercalated between the cathode 16 and electrolyte 18. The compositelayer 28 comprises a lithium ion conductive glass ceramic layer (LI-GC)30 adjacent the electrolyte 18 and a lithium ion conductive barrier film(LI-BF) 32 interposed between the ceramic layer 30 and cathode 18. Thebarrier layer 32 and glass ceramic layer 30 composite 28 isolatesforming lithium at cathode 16 from electrolyte 18. Shaft 26 advances thecathode 16 and composite 28 as lithium metal is formed and depositedthrough the composite layer 28 onto the advancing cathode 16. TheLithium metal produced at the solid cathode 16 can be drawn off as apure metallic phase.

Suitable feed to the cell includes water-soluble lithium salts includingbut not limited to Li₂CO₃ and LiCl. To improve solubility, the lithiumsalt is dissolved in hydrated acid and used as electrolyte in theelectrolytic cell. Lithium Carbonate (Li2CO3) was used as feed stock forinitial trials.

Some suitable cell components in the present invention are described inUS20130004852, which is incorporated into this disclosure in itsentirety by reference.

Suitable electrolyte 18 components include water-soluble lithium saltsincluding but not limited to Li₂CO₃ and LiCl. To improve solubility thelithium salt can be dissolved in hydrated acid to be used aselectrolyte. Lithium carbonate (Li₂CO₃) is the most readily availablelithium salt, being relatively inexpensive and is a preferred lithiumsource. Cathode 16 is characterized by the intercalated composite(Li-GC/Li-BF) 28 meaning the composite 28 is inserted or interposedbetween the cathode 16 and electrolyte 18. The cathode 16 can becharacterized as “transpositioning” meaning the cathode advances alongan axis of the cell 10 to transpire produced lithium through thecomposite 28 and to isolate cathode-deposited lithium. The cathodecomprises a suitable material that is non-reactive with lithium metaland the composite layer. The Li-GC/Li-BF composite layer is a stationarybarrier between the anode compartment and the lithium metal forming onthe cathode. The cathode moves to accommodate the continuouslythickening layer of lithium metal on the cathode.

Composite layer (Li-GC/Li-BF) 28 includes lithium ion conductive glassceramic layer (LI-GC) 30 and lithium ion conductive barrier film (LI-BF)32. The substantially impervious layer (LI-GC) 30 can be an active metalion conducting glass or glass-ceramic (e.g., a lithium ion conductiveglass-ceramic that has high active metal ion conductivity and stabilityto aggressive electrolytes that vigorously react with lithium metal.Suitable materials are substantially impervious, ionically conductiveand chemically compatible with aqueous electrolytes or other electrolyte(catholyte) and/or cathode materials that would otherwise adverselyreact with lithium metal. Such glass or glass-ceramic materials aresubstantially gap-free, non-swellable and are inherently ionicallyconductive. That is, they do not depend on the presence of a liquidelectrolyte or other agent for their ionically conductive properties.They also have high ionic conductivity, at least 10⁻⁷ S/cm, generally atleast 10⁻⁶ S/cm, for example at least 10⁻⁵ S/cm to 10⁻⁴ S/cm, and ashigh as 10⁻³ S/cm or higher so that the overall ionic conductivity ofthe multi-layer protective structure is at least 10⁻⁷ S/cm and as highas 10⁻³ S/cm or higher. The thickness of the layer is preferably about0.1 to 1000 microns, or, where the ionic conductivity of the layer isabout 10⁻⁷ S/cm, about 0.25 to 1 micron, or, where the ionicconductivity of the layer is between about 10⁻⁴ about 10⁻³ S/cm, about10 to 1000 microns, preferably between 1 and 500 microns, and morepreferably between 50 and 250 microns, for example, about 150 microns.

Examples of glass ceramic layer (LI-GC) 30 include glassy or amorphousmetal ion conductors, such as a phosphorus-based glass, oxide-basedglass, phosphorus-oxynitride-based glass, sulfur-based glass,oxide/sulfide based glass, selenide based glass, gallium based glass,germanium-based glass or boracite glass (such as are described D. P.Button et al., Solid State Ionics, Vols. 9-10, Part 1, 585-592 (December1983); ceramic active metal ion conductors, such as lithiumbeta-alumina, sodium beta-alumina, Li superionic conductor (LISICON), Nasuperionic conductor (NASICON), and the like; or glass ceramic activemetal ion conductors. Specific examples include LiPON, Li₃PO₄.Li₂S.SiS₂,Li₂S.GeS₂.Ga₂S₃, Li₂O.

Suitable glass-ceramic materials (LI-GC) include a lithium ionconductive glass-ceramic having the following composition in molpercent: P₂O₅ 26-55%; SiO₂ 0-15%; GeO₂+TiO₂ 25-50%; in which GeO₂ 0-50%;TiO₂ 0-50%; ZrO₂ 0-10%; M₂O₃ 0-10%; Al₂O₃ 0-15%; Ga₂O3 0-15%; Li₂O 3-25%and containing a predominant crystalline phase comprising Li_(1+x)(M,Al, Ga)_(x)(Ge_(1-y)Ti_(y))_(2-x)(PO₄)₃ where X≦0.8 and 0≦Y≦1.0 andwhere M is an element selected from the group consisting of Nd, Sm, Eu,Gd, Tb, Dy, Ho, Er, Tm and Yb, and/or Li_(1+x+y)Q_(x)Ti_(2-x)Si₃P3-yO₁₂where 0<X≦0.4 and 0<Y≦0.6, and where Q is Al or Ga. Other examplesinclude 11Al₂O₃, Na₂O.11Al₂O₃, (Na, Li)_(i+)xTi_(2-x)Al_(x)(PO₄)₃(0.6≦x≦0.9) and crystallographically related structures, Na₃Zr₂Si₂PO₁₂,Li₃Zr₂Si₂PO₄, Na₅ZrP₃O₁₂, Na₅TiP₃O₁₂, Na₃Fe₂P₃O₁₂, Na₄NbP₃O₁₂,Li₅ZrP₃O₁₂, Li₅TiP₃O₁₂, Li₅Fe₂P₃O₁₂ and Li₄NbP₃O₁₂ and combinationsthereof, optionally sintered or melted. Suitable ceramic ion activemetal ion conductors are described, for example, in U.S. Pat. No.4,985,317 to Adachi et al., incorporated by reference herein in itsentirety.

Suitable LI-GC material includes a product from Ohara, Inc. (Kanagawa,JP), trademarked LIC-GC™, LISICON, Li₂O—Al₂O₃—SiO₂—P₂O₅—TiO₂ (LATP).Suitable material with similarly high lithium metal ion conductivity andenvironmental/chemical resistance are manufactured by Ohara and others.See for example, Inda, DN20100113243, now U.S. Pat. No. 8,476,174,incorporated herein in their entirety by reference. U.S. Pat. No.8,476,174 discloses a glass-ceramic comprising at least crystallineshaving a having a LiTi₂P₃O₁₂ structure, the crystallines satisfying1<I_(A113)/I_(A104)≦2, wherein I_(A104) is the peak intensity assignedto the plane index 104 (2Θ=20 to 21°), and I_(A113) is the peakintensity assigned to the plane index 113 (2Θ=24 to 25°) as determinedby X-ray diffractometry.

The lithium ion conductive barrier film 32 (Li-BF) is a lithium metalion conductive film or coating with high lithium metal ion conductivity,typically The lithium ion conductive barrier film 32 (LI-BF) is alithium metal ion conductive film or coating with high lithium metal ionconductivity, typically 1.0 mS/cm to 100 mS/cm. A high lithium iontransference number (t₊) is preferred. Low t₊Li⁺ electrolytes willhinder performance by allowing ion concentration gradients within thecell, leading to high internal resistances that may limit cell lifetimeand limit reduction rates. Transference numbers between t₊=0.70 andt₊=1.0 are preferred. The lithium ion conductive barrier film isnon-reactive to both lithium metal and the LI-GC material.

The LI-BF film 32 includes an active metal composite, where “activemetals” are lithium, sodium, magnesium, calcium, and aluminum used asthe active material of batteries. Suitable LI-BF material includes acomposite reaction product of active metal with Cu₃N, active metalnitrides, active metal phosphides, active metal halides, active metalphosphorus sulfide glass and active metal phosphorous oxynitride glass(Cu₃N, L₃N, Li₃P, LiI, LiF, LiBr, LiCl and LiPON). The LI-BF materialmust also protect against dendrites forming on the cathode from comingin contact with the LI-GC material. This may be accomplished by creatingphysical distance between the cathode and LI-GC and/or providing aphysical barrier that the dendrites do not penetrate easily. Onepreferred LI-BF film is a physical organogel electrolyte produced by insitu thermo-irreversible gelation and single ion-predominant conductionas described by Kim et al. in Scientific Reports athttp://www.nature.com/srep/2013/130529/srep01917/fig_tab/srep01917_F1.html.(article number: 1917 doi:10.1038/srep01917). This electrolyte hast₊=0.84 and conductivity of 8.63 mS/cm at room temperature. Thisorganogel electrolyte can be set up in a porous membrane to provideadditional structure and resistance to dendrite penetration. Typicalporous membrane thickness is 1 um to 500 um, for example 20 um.Acceptable porous membrane includes HIPORE polyolefin flat-film membraneby Asahi Kasei E-materials Corporation.

The invention produces lithium metal that can be used as part of acontinuous lithium metal production process. In particular, the presentprocess can utilize inexpensive lithium carbonate or an equivalentsource of lithium ions. The process can be used to produce lithium metaldirectly from the acid solution used to leech lithium metal out ofspodumene ore or other natural lithium sources.

Features of the invention are apparent from the drawings and followingdetailed discussion, which by way of example without limitation describeone preferred embodiments of the invention.

EXAMPLE

The cell used is shown schematically in FIG. 3. The cell 110 includescell cover 116, retainer 118, Pt anode 112, cathode 124 and a LI-GCconductive glass 114 with lithium ion conductive barrier film 120incorporated into a porous polyolefin flat-film membrane 122. Thesupported LI-GC-BF multilayer is intercalated between cathode 124 and alithium ion-rich electrolyte 18 (in FIGS. 1 and 2). The cell furthercomprises supporting Teflon® sleeve structure 126 with gaskets 128. Onegasket seals between the LI-GC and the housing to prevent leakage of theelectrolyte from the anode compartment into the cathode compartment. Theother gasket allows for even compression of the LI-GC by the TeflonSleeve to prevent breakage of the LI-GC plate.

The cell 110 includes anode 112 that is a platinized titanium anode,1″×4″ rhodium and palladium jewelry plating). The cathode is a palladiumcathode disk fabricated in-house, 1.4 inch round. The LI-GC 114 materialis LICGC® G71-3 N33: DIA 2 IN×150 um Tape cast, 150 um thick, 2 inchround from Ohara Corporation, 23141 Arroyo Vista, Rancho SantaMargarita, Calif. 92688.

The lithium ion conducting gel electrolyte 120 is fabricated from: aPVA-CN polymer supplied by the Ulsan National Institute of Science andTechnology in Ulsan South Korea, Dr. Hyun-Kon Song,UNIST/82.52.217.2512/echem.kr., procured from Alfa Aesar, stock numberH61502; LiPF6 (Lithium hexafluorophosphate), 98%,; EMC (ethyl methylcarbonate), 99%, from Sigma Aldrich, product Number 754935; EC (ethylenecarbonate), anhydrous, from Sigma Aldrich, product number 676802 and aporous membrane, ND420 polyolefin flat-film membrane from Asahi Corp.

The LI-BF bather layer 120 is fabricated in an argon purged glove bag.The glove bag is loaded with all materials, precision scale, syringes,and other cell components then filled and evacuated 4 times before thestart of the electrolyte fabrication process.

The organogel electrolyte is mixed up as follows: 4.0 ml of EMC isliquified by heating to about 140° F., and placed in a vial. 2.0 ml ofthe EMC is then added-to the vial 0.133 g (2% wt) PVA-CN polymer isadded to the vial and the is agitated for 1 hour to dissolve the PVA-CN.Then 0.133 g (2% wt) FEC is added as SEI-forming additive 0.972 g (1M)LiPF6 is then added and mixed to complete the organogel electrolytemixture. The electrolysis cell is then assembled inside the glove bag.With the LI-GC and gaskets in place, the anode and cathode compartmentsare sealed from each other. The organogel electrolyte mixture is used towet the cathode side of the LI-GC, the HIPORE membrane is placed on thecathode side of the LI-GC and wetted again with organogel electrolytemixture. The cathode disk is then placed on top of the organogelmixture. The cell is placed in a Mylar® bag and sealed while still underargon purge. The sealed Mylar® bag with assembled cell is then placed inan oven at 60 C for 24 hours to gel the electrolyte.

The electrolysis cell 10 is removed from the oven and placed in theargon purged glove bag, and allowed to cool to room temperature. Clearpolypro tape is used to seal the empty space above the cathode disc andsecure the electrode wire. The electrolysis cell 10 is now ready foruse, is removed from the glove bag, and is connected to the electrolytecirculating system.

An electrolyte 18 is prepared with 120 g of lithium carbonated in 200 mlof deionized water and 500 ml of 20% wt sulfuric acid. The sulfuric acidis slowly added to the lithium carbonate suspension and mixed well.Undissolved lithium carbonate is allowed to settle. A supernatant iscollected from the stock solution, an 18% wt lithium stock solution. The18% wt lithium solution has a measured pH of 9. Solution pH is loweredby addition of 20% wt sulfuric acid. Again, the sulfuric acid is addedslowly to minimize foaming. The 18% wt lithium stock solution isadjusted to pH 4.5. Preferred PH is between PH3.0 and PH4.5, mostpreferred is between PH3.0 and PH4.0, but process can be run at PH7.0 orbelow. PH above 7.0 will result in carbonate in solution.

The electrolyte mixture is then poured into the circulating system. Thecirculating pump is primed and solution circulated for 30 minutes tocheck for leaks.

The lithium ion-rich electrolyte 18 flows through the top half of cell110 over the LI-GC-BF multilayer 114/120 and past anode 112. Whenpotential is applied to the system, lithium metal builds up on themoving cathode below the LI-GC-BF multilayer 114/120 system.

A Gamry Reference 3000 Potentiostat/Galvanostat/ZRA is attached to thecell 10. At voltages of 3-6 volts there is no significant activity. Whenvoltage is raised to 10V the system responds. Amperage draw increaseswhen voltage is raised to 11 vdc. No gassing on the anode side of thecell was noted at 11 vdc. The Gamry Reference 3000 would not go above 11vdc. Since no gassing occurred at 11 vdc the reduction rate could mostlikely be much higher if voltage were increased. An even higher voltageand reduction rate are preferable if achieved with negligible oxygenproduction at the anode. PH of the electrolyte at time zero is 4.46. PHof the solution decreases to 4.29 after 35 minutes, and is 4.05 at theend of the experiment. The lowering PH indicates lithium ion removalfrom the electrolyte solution.

An amperage draw of 20 mA is noted at the start of the experiment. Theamperage draw slowly increased to 60 mA after 30 minutes. Amperage holdsfairly steady at this value for another 30 minutes. Experiment timer andgraph are paused for 30 minutes to extend experiment (voltage held at 11vdc). After approximately 65 minutes of run time a large amperage spikeand sudden vigorous gassing is noted on the anode side of the cell Thisis indicative of LiCGC 114/120 membrane failure.

Rapid gassing and bright white flame is observed when the cell 10 isopened and cathode 16 side is exposed to electrolyte leaking through theLI-GC 114/120, evidencing that the cell produces lithium metal byelectrolysis of lithium ions in a sulfuric acid aqueous solution,through a LI-GC-BF 114/120 membrane system.

While preferred embodiments of the invention have been described, thepresent invention is capable of variation and modification and thereforeshould not be limited to the precise details of the Examples. Theinvention includes changes and alterations that fall within the purviewof the following claims.

What is claimed is:
 1. A lithium producing cell structure, comprising: a cell body with a cathode within the cell body; a sulfuric acid solution within the cell body, the solution containing lithium ion and an anion; and a composite layer intercalated between the cathode and the electrolyte aqueous solution, the composite layer comprising a lithium ion conductive glass ceramic (LI-GC) and a lithium ion conductive barrier film (LI-BF) that isolates cathode-forming lithium from the electrolyte aqueous solution.
 2. The lithium producing cell of claim 1, wherein the composite layer is characterized by high lithium metal ion conductivity and is nonreactive to both lithium metal and the LI-GC material.
 3. The lithium producing cell of claim 1, wherein the lithium ion conductive barrier film of the composite layer comprises a physical organogel electrolyte.
 4. The lithium producing cell of claim 1, wherein the lithium ion conductive barrier film of the composite layer comprises an organogel product of an in situ thermo-irreversible gelation and single ion-predominant conduction.
 5. The lithium producing cell of claim 1, wherein the composite layer comprises a lithium ion conductive glass ceramic and a lithium ion conductive barrier film.
 6. The lithium producing cell of claim 1, wherein the substantially impervious ionically conductive polymeric separator layer comprises a glass-ceramic active metal ion conductor.
 7. The lithium producing cell of claim 1, wherein the lithium ion conductive glass ceramic (LI-GC) is an ion conductive glass-ceramic having the following composition in mol percent: P₂O₅ 26-55%; SiO₂ 0-15%; GeO₂+TiO₂ 25-50%; in which GeO₂ 0-50%; TiO₂ 0-50%; ZrO₂ 0-10%; M₂O₃ 0-10%; Al₂O₃ 0-15%; Ga₂O3 0-15%; Li₂O 3-25% and containing a predominant crystalline phase comprising Li_(1+x)(M, Al, Ga)_(x)(Ge_(1-y)Ti_(y))_(2-x)(PO₄)₃ where X≦0.8 and 0≦Y≦1 and where M is an element selected from the group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb, and/or Li_(1+x+y)Q_(x)Ti_(2-x)Si₃P3-yO₁₂ where 0<X≦0.4 and 0<Y≦0.6, and where Q is AI or Ga.
 8. The lithium producing cell of claim 1, wherein the composite layer has an ionic conductivity of at least 10⁻⁴ S/cm.
 9. The lithium producing cell of claim 1, wherein the cathode comprises a catholyte selected from the group consisting of non-aqueous electrolyte
 10. The lithium producing cell of claim 1, wherein the cathode further comprises electrochemically active material selected from the group consisting of solid, liquid and gaseous oxidizers.
 11. The lithium producing cell of claim 1, wherein the catholyte comprises an ionic liquid.
 12. The lithium producing cell of claim 1, wherein the composite layer comprises a substantially impervious protective ceramic composite layer and the lithium ion conductive barrier film.
 13. The lithium producing cell of claim 1, wherein cathode is movable along an axis of the cell.
 14. A process for producing lithium, comprising: providing a lithium ion source in a sulfuric acid solvent wherein lithium anion is dissolved in the solvent to form a lithium feed solution; providing an anode in contact with the solution; providing a cathode suitable for electrolysis of lithium, wherein the cathode in contact with the solution through a composite ion-conducting barrier forms an electrolysis cell; providing an ionizing electric current to the electrolysis cell thereby producing lithium metal at the cathode; and providing a composite layer transecting an axis of the cell body, the composite layer, comprising a lithium ion glass ceramic and lithium, ion conductive barrier film that isolates cathode-forming lithium from the anion-containing solution as lithium metal is formed.
 15. The process for producing lithium of claim 14, wherein the composite layer is characterized by high lithium metal ion conductivity and is nonreactive to both lithium metal and the LI-GC material
 16. The process for producing lithium of claim 14, wherein the cathode is drivable along a cell axis away from anode as lithium metal is deposited on the cathode.
 17. The process for producing lithium of claim 14, wherein, the cell is postured with upper moving cathode and lower cell containing electrolyte to drive the cathode away from the composite ion conducting layer as lithium metal is deposited on the cathode.
 18. The lithium producing cell of claim 14, wherein the lithium ion conductive barrier film of the composite layer comprises a physical organogel electrolyte.
 19. The lithium producing cell of claim 14, wherein the lithium ion conductive barrier film of the composite layer comprises an organogel product of an in situ thermo-irreversible gelation and single ion-predominant conduction.
 20. The process of claim 14 where the lithium ion source is lithium carbonate
 21. The process of claim 14 where the lithium ion source is another lithium salt which dissociates in an acid solvent placing the lithium ions into solution and releasing the non-lithium portion of the salt as a gas.
 22. The process of claim 14 where the acid is other than sulfuric acid but dissociates the lithium source in the same manner, placing lithium ions into solution while releasing the non-lithium portion of the source as a gas. 